The present invention relates to a new synthetic ester oil usable as a substitute for lanolin, as well as cosmetics, toiletries and external preparations including drugs and quasi-drugs containing it.
Lanolin is incorporated into various cosmetics and toiletries and used as a base for ointments in virtue of its excellent properties such as adherability, wettability and emulsifiability. However, it was often pointed out that lanolin has a color and smell peculiar to animal oils and fats and it also has defects due to complicated substances contained therein and unstable quality thereof. Although lanolin recently available on the market has a high purity, since it is purified by a purification process comprising various steps, the essential defects thereof still remain. Further the use of lanolin tends to be indirectly controlled by recent worldwide tendency to prevention of cruelty to animals and conservation of nature.
Under these circumstances, investigations were heretofore made for the purpose of developing a substance similar to lanolin or usable as a substitute for lanolin. For example, Japanese Patent Publication for Opposition Purpurse (hereinafter referred to as "J. P. KOKOKU") Nos. Sho 61-7168 and Sho 61-7403 propose esterifcation products prepared from a polyhydric alcohol such as glycerol, diglycerol, trimethylolpropane, pentaerythritol or sorbitol and a monobasic acid having 8 to 22 carbon atoms or dibasic acid having 12 to 20 carbon atoms as substances having characteristics similar to those of lanolin and vaseline. Further Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Sho 58-198565 propoes equimolar mixed esters such as pentaerythritol/dicoconut fatty acid ester and di-octadecyl citrate, as well as a mixture of oleic acid monodiglyceride, palmitic acid and/or stearic acid mono-diglyceride and ethylene oxide-added vegetable sterol as substitutes for wool wax.
However, the lanolin-like substances or substitutes for lanolin heretofore proposed were inferior to lanolin, since they are heavy to the touch and have insuffucient spreadability and adherability and the constituents are separated out during storage. This fact indicates that a substitute for lanolin cannot be easily chemically synthesized, since lanolin is a natural product having an extremely complicated composition containing minor constituents peculiar to the natural oils and fats such as esters of short to long, linear and branched, saturated and unsaturated carboxylic acids, hydroxy acids, dicarboxylic acids, etc. with cholesterol, lanosterol, etc. In other words, development of an oil-like substance having the characteristics of lanolin but free from the defects thereof or development of stable cosmetics, toiletries and external preparations such as drugs and quasi-drugs containing it has been demanded.